Semiconductor crystal-structure-processed mechanical devices, and methods and systems for making

ABSTRACT

Processing and systems to create, and resulting products related to, very small-dimension singular, or monolithically arrayed, semiconductor mechanical devices. Processing is laser performed on selected semiconductor material whose internal crystalline structure becomes appropriately changed to establish the desired mechanical properties for a created device.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention arises from a new area of recognition anddevelopment focussed on the technology of low-temperature,crystalline-structure-processed devices, and in particular mechanical,mechanical and electrical, so-called MEMS (micro-electromechanical),layered and stacked devices, and devices organized into monolithicarrays in layers, that opens up a broad new field of potential devicesand applications not heretofore so inexpensively and conveniently madepractical and practicable. This new field of possible devices, fromwhich a number of inventions, one of which is specifically addressed inthis disclosure, springs effectively from the recognition that internalcrystalline-structure processing performed within the bodies of a widevariety of different materials, is capable of enabling fabrication ofsmall (perhaps even down to devices formed from small molecularclusters), versatile, widely controllable and producible, accurate,mechanical, electromechanical and MEMS devices that can be formed veryinexpensively, and, with respect to laser processing, in uncontrolledand room-temperature environments not requiring vacuum chambers, etc.

Especially, the invention offers significant opportunities for thebuilding, relatively cheaply and very reliable, of very tinysemiconductor mechanical devices that can be deployed in densetwo-dimensional and three-dimensional complex arrays and stackedarrangements. These devices can take on a large range of differentconfigurations, such as individuated, single-device configurations,monolithic single-layer array arrangements of like devices, similarmonolithic arrays of combined electrical and mechanical devices, and invertically integrated and assembled stacks and layers of complexdevices, simply not achievable through conventional prior art processesand techniques. By enabling room-temperature fabrication, otherwiseeasily damaged and destroyed layer-supporting substrates, includingfabricated-device under-layers, can readily be employed.

The field of discovery and recognition which underpins the inventiondisclosed herein, can be practiced with a very wide range ofsemiconductor materials in arrays that can be deployed on rigidsubstrates of various characters, and on a wide range of flexiblematerials, such as traditional flex-circuit materials (polymers andplastics), metallic foil materials, and even fabric materials.Additionally, the field of development from which the present inventionemerges can be employed with large-dimension bulk materials, as well aswith various thin-film materials. The present invention is described inthis broader-ranging setting. With regard to the latter category ofmaterials, the process of this invention can take advantage oftraditional thin-film semiconductor processing techniques to shape andorganize unique devices, which are otherwise prepared in accordance withthe internal crystalline-structure-processing proposed by the presentinvention, thus to achieve and offer mechanical properties in a broadarena of new opportunities.

In this setting, the invention disclosed in this document isspecifically related to crystal-structure-processed semiconductormechanical devices, either as individuated, single devices, or in arraysof devices organized into monolithic, layer-type arrangements, as wellas to methodology and system organizations especially suited to thepreparation and fabrication of such devices. The invention proposed aunique way, employing, for example, different types of lasers and otherillumination sources. effectively to “reach into” the internalcrystalline structures different semiconductor materials for the purposeof controllably modifying those structure to produce advantageousmechanical properties in devices, and at sizes very difficult andsometimes not even possible to create via prior art techniques.

From the drawings and the descriptions which now follow, it will becomereadily apparent how the present invention lends itself to the economic,versatile, multi-material fabrication and use of a large variety ofdevices, ranging from relatively large devices to extremely small device9 as mentioned earlier), and including various forms of MEMS devices,without the fabrication of these devices, insofar as laser processinginvolved, necessitating the use of special controlled processingenvironments, or surrounding processing temperatures above typical roomtemperature.

With this in mind, the significant improvements and specialcontributions made to the art of device-fabrication according to theinvention will become more fully apparent as the invention descriptionwhich now follows is read in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block/schematic view illustrating a system which implementsthe methodology of this invention for the creation of single or arrayedsemiconductor mechanical devices in accordance with the presentinvention.

FIG. 2 is a schematic diagram illustrating single-side, full-depthinternal-crystalline-structure laser processing to create asemiconductor mechanical device in accordance with the invention.

FIG. 3 is very similar to FIG. 2, except that here what is shown istwo-sided processing according to the invention.

FIG. 4 is a view similar to FIG. 2, but here showing processingoccurring from an opposite side of material in accordance with theinvention.

FIG. 5 is a view illustrating single-side, partial-depthinternal-crystalline-structure processing according to the invention.

FIG. 6 is similar to FIG. 2, except that here single-side processingincludes a flood, or wash, of general heating illumination according toone form of practicing the invention, with this illumination strikingmaterial on what is shown as the upper side in FIG. 6.

FIG. 7 is similar to FIG. 6, except that it illustrates two-sidedprocessing wherein a relatively translated laser beam processes theupper side of material as pictured in FIG. 7, and a wash, or flood, ofother illumination (from a laser or another light soruce) aids from thebottom side of material as pictured in FIG. 7. FIG. 7, in particular,illustrates a condition where material that is being processed inaccordance with the invention is resting on a substrate which is nottransparent to the wash of illumination coming from the bottom side ofFIG. 7.

FIG. 8 is similar to FIG. 7, except that here the material beingprocessed is resting on a substrate, such as glass, which is essentiallytransparent to a wash of illumination striking from the bottom side ofFIG. 8.

FIGS. 9 and 10 illustrate two different views of a stylizedmicro-cantilever beam structure (mechanical device) constructed inaccordance with the invention.

FIG. 11 shows an isolated view of a single micro-cantilever mechanicalbeam structure with a darkened region presented in this figure toillustrate, variously, sensitizing of a surface of the beam for thedetection of a mechanical event, a chemical event, a biological event,etc. and also generally suggesting how, nested within the mechanicalmaterial making up the cantilever beam of FIG. 11 an electronicstructure, such as a transistor, could be formed in a portion of thecantilever beam.

FIG. 12 is a view illustrating single-side, full-depth internalcrystalline-structure processing of bulk material in accordance with thepresent invention.

FIG. 13 is similar to FIG. 12, except that here what is shown issingle-side, partial depth, bulk-material processing. FIGS. 12 and 13are included to give a broad understanding of the underlying overallfield in which the present invention finds its place.

FIG. 14 is a view illustrating internal-crystalline-structure processingemploying a single-crystal seed which is employed to characterize theend-result internal crystalline structure that can be achieved in thematerial pictured in FIG. 14.

FIG. 15 is a stylized, schematic, isometric view illustratingfragmentarily a single planer array of plural mechanical devicesprepared in a single monolithic, generally planar structure inaccordance with the present invention.

In FIGS. 2, 3, 4, 5, 6, 7, 8, 12 and 13, the darkened regions in thematerial being processed represents the processed regions in thesematerials.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings, and referring first of all to FIG. 1,illustrated generally at 20 is a system which is employed according tothe present invention to implement a methodology for processing theinternal crystalline structure of various different semiconductormaterials in accordance with the invention, and all for the purpose ofcreating one or more mechanical devices that are intended to performrespective, predetermined, pre-chosen tasks. Included in system 20 are ablock 22 which represents a suitably programmed digital computer, ablock 24 which is operatively connected to block 22, and whichrepresents the presence of appropriate laser structure and controls,such as beam-shaping and optics controls using optical or maskingmethods, fluency controls, angularity controls, and other, for definingthe functional characteristics of a appropriate laser beam shown at 26which is to be employed in accordance with the invention to produceinternal crystalline-structure processing of any one of a number ofdifferent semiconductor materials, as will be more fully mentionedbelow. In FIG. 1, a material for processing is shown generally at 28,with this material having a layer form, and being suitably supported onan appropriate supporting substrate 30 which rests upon, and is anchoredto, a three-axis translation table (a driven table) 32.

Table 32 is drivingly connected to a motion drive system, represented byblock 34 in FIG. 1, which drive system is under the control of computer22. This motion drive system, under the control and influence ofcomputer 22, is capable of translating table 32, and thus materialsupported on this table, in each of the three usual orthogonal axesknown as the X, Y, and Z axes, such axes being pictured at the rightside of FIG. 1. Very specifically, control over motion of table 32 isdirected by an appropriate algorithm 36 which is resident withincomputer 22, and which, fundamentally, is equipped to direct a laserbeam for processing in accordance with device configuration and deviceinternal mechanical properties that have been chosen and selected, andfor which algorithm 36 is especially designed.

The exact nature of the construction of computer 22, of controls 24, ofalgorithm 36, and of the driven table and the motion drive therefor,form no part of the present invention, and accordingly are not furtherdetailed herein.

Fundamentally, what takes place in the operation of system 20 to producea given type of mechanical device is that a user selects a particularkind of device to build, selects an appropriate size and configurationfor that device, and then determines what are the best and mostappropriate internal mechanical properties that should be created inthat device in order to enable it to function properly with respect toimplementing a selected task. In general terms, the semiconductormaterials out of which a particular material can be selected to producesuch a device are those whose internal crystalline structures areclosely linked to the material's mechanical properties. Specifically,the various useable semiconductor materials are those whose internalcrystalline structures can be modified by laser processing to producedesired mechanical properties for a device. Various materials withrespect to which the present invention can conveniently and verysuccessfully work will be discussed very shortly, but it might be notedat this point that these materials, with respect to their precursorstates, i.e. their states before processing, range from fully amorphousmaterials through and into a range of various categories ofpolycrystalline materials.

For example, practice of the invention can begin with precursor materialwhich can fit into any one of the following categories: amorphous,nanocrystalline, microcrystalline, and polycrystalline. All suchmaterials can be generally described as having an internal crystallinestructure which, initially in a precursor state, is less than singlecrystalline in nature.

Semiconductor materials which can very successfully be processed inaccordance with this invention include silicon, germanium andsilicon-germanium. For the purpose of further illustration in thisdescription, a manner of practicing the invention, and a device emergingfrom that practice, will be described in conjunction withfull-layer-depth processing of a precursor amorphous silicon material,which will thus be treated as the specific kind of material which ispictured at 28 in FIG. 1. Also for the purpose of focused illustrationherein, this precursor illustrative amorphous silicon material isdeployed as an appropriate thin layer on a glass substrate, which isdesignated by reference numbered 30 in FIG. 1. Other substratematerials, as will become apparent, may include quartz, various metals,plastics, flex materials, fabrics and others. All of these materialshave what are referred herein as relatively low melting (or destruction)temperatures which are well below the melting temperature of the siliconprecursor material.

As has already been suggested above, practice of the present inventioncan produce a wide variety of uniquely configured and constructedsemiconductor mechanical devices which can be extremely small in size,ranging down even to a small molecular cluster size. Devices which canbe produced include various MEMS devices, micro-mechanical devices thatare sensitized to act as sensors for various environmental events, suchas chemical and biological events, various motion elements generally,oscillating elements, cantilever beams, actuators, relay switches, andother devices.

With respect to formation of a particular device's three-dimensionalconfiguration, this can be done in any one of a number of conventionallyknown ways. The exact processes employed to give three-dimensionaldefinition to a finally produced device, as for example to singulate anelement from a mass of material in which it has been formed, and/or toindividuate (for performance purposes) plural devices in a monolithicarray of devices, can take the form of various conventional processeswhich form no particular parts of the present invention. Thus they arenot discussed herein in detail.

For the purpose of illustration herein, processing will be described inthe setting, initially, of creating a single micro-mechanical cantilevermechanical device, using single-side, translated laser-beam processing.While various specific types of lasers can be employed such as a excimerlaser, a solid-state laser, a continuous-wave laser, and a femto laser,to name several, description will proceed in the context of using anexcimer laser.

Describing now a typical practice implemented by the present invention,an amorphous silicon layer having an appropriate precursor thickness issuitably formed on the surface in a glass substrate, such as substrate30. This assembly is placed on table 32 with appropriate initialalignment, and is then translated relatively with respect to a laserbeam, such as excimer laser beam 26, which beam is pulsed duringtranslation of the material relative to the source of the laser beam, toproduce full-depth, small-area quick melting and re-crystallizing of thesilicon material. An appropriate excimer laser, driven and pulsed at anappropriate pulse rate, and with an appropriate fluency and footprint inthe sense of how and with what outlines it strikes the surface of theamorphous silicon material, is directed toward this surface under thecontrol of computer 22, algorithm 36, and controls 24.

In accordance with the desired end-result internal crystallinestructure, and in a relative motion sense, the impingement point of thisbeam from a laser is moved in a defined way over the surface of theamorphous silicon material to produce rapid, full-depth melting andre-crystallizing in a manner designed to achieve the pre-determineddesired internal crystalline structure. Employing an excimer laser inthis fashion allows one to process material in such a fashion that thehigh-temperature events are essentially confined very locally to theregions specifically where material melt is occurring. Very little, andno dangerous, temperature rise occurs in the surrounding area, such aswithin substrate 30, and the whole process can take place in a normalatmospheric environment and completely at room temperature.

FIGS. 2, 3 and 4 show several different approaches to implement suchlaser processing. In FIG. 2 the laser beam strikes the surface of theamorphous silicon material on the upper side which is spaced away fromsupporting substrate 30. Processed material is indicated (darkened) at27. In FIG. 3 dual-sided processing takes place with two laser beamscooperating on opposite sides of the material, with the lower beameffectively processing the underside of the silicon material through thetransparency afforded by glass substrate 30. Such dual-sided laserprocessing effectively allows melting and re-crystallizing to take placesimultaneously on opposite sides of the supported silicon material, andwith each laser, therefore, requiring only a portion of the powerrequired for similar processing to take place under the influence of asingle laser beam. Where a mask is employed for beam shaping, thisdual-laser approach promotes longer-term durability of such a mask—atypically expensive device, and which is subject to significantdegradation at high laser power levels Two-sided dual-beam processingcan also be effective to allow processing to be performed in otherwisedifficult to reach areas with just a single processing beam.

In FIG. 4 single-side processing is demonstrated where, in this case,the processing laser beam is directed toward the silicon material fromthe bottom side (i.e. the substrate supported side) of this material.

FIG. 5 illustrates single-side, less than full-depth processing of thesilicon material, here employed to create ultimately a mechanical devicewhich effectively becomes a device that is composited with unprocessedmaterial lying beneath it, as illustrated in FIG. 5.

FIGS. 6, 7 and 8 show different manners of modifying the kinds of laserprocessing illustrated in FIGS. 2-4 inclusive, and specifically amodified processing approach which employs an additional broad area washof illumination 38 from another illumination source which could be, butis not necessarily, a laser source. In FIG. 6 this wash of illuminationstrikes the upper side of the silicon material in companionship withlaser beam 26, and is effective essentially to create an overalltemperature rise in the silicon material which permits a lower energylaser beam to perform appropriate full-depth processing. In FIGS. 7 and8 this wash 38 of illumination is directed toward the underside of thesilicon material and the supporting substrate, with FIG. 7 illustratinga condition where the substrate support material shown at 40 is nottransparent to illumination. In this implementation of the invention,the silicon material which is being processed is heated in a conductionmanner through heating of substrate 40. In FIG. 8, glass substrate 30 isagain pictured, and here, the wash 38 of illumination passes throughthis substrate to heat the silicon material above the substratedirectly.

According to practice of the invention, once a particular semiconductormechanical device to build has been decided upon, the desired threedimensional configuration of this device is chosen, and algorithm 36 isdesigned to direct laser processing in such a fashion as to create aregional volume of material within the processed material on thesubstrate adequate for the ultimate individuation and singulation, ifthat is what is desired, of an end-result mechanical device. With such achosen device configuration in mind, the most desired internalmechanical properties are predetermined, and algorithm 36 is alsoconstructed so that it will control the operation of a laser beam, suchas beam 26, to produce internal melting and re-crystallization in orderto achieve an internal crystalline structure that will yield the desiredmechanical properties. In some instances, it may be more appropriate tocreate differentiated regions of crystalline structure within a devicebeing built in order to produce different specific mechanical propertiesin different within that material. Such is entirely possible utilizingthe processing approach which has just been outlined above.

FIGS. 9 and 10 show a side cross section and an idealized top plan viewof a stylized cantilever-beam mechanical device 42 which has been sodefined by processing within the body of silicon material 28.

FIG. 11, in an idealized fashion, isolates an illustration of cantileverbeam 42, and shows by way of suggestion, produced by the darkened patchwhich appears in FIG. 11, how an appropriate event sensor, such as achemical sensor, a biological sensor, and other kinds of sensors couldbe applied, in any suitable manner, to the beam so as to respond toselected environmental events in a manner which causes deflection in thebeam. The present invention is not concerned with the specific kinds ofsensitivity for which a device, such as beam 42, is to be prepared, andthus details of how sensitizing can take place are not presented herein.

FIG. 11 can also be read to illustrate yet another interesting componentoffering of the present invention which is that it is possible to createwithin the mechanical body of the device, such as cantilever beam 42, anelectronic device, such as a semiconductor transistor which can bethought of as being represented by the darkened patch appearing in FIG.11.

FIGS. 12 and 13 illustrate use of the invention to modify internalcrystalline structure inside a bulk material 43, either with afull-depth approach (FIG. 12) or with a partial-depth approach (FIG. 13)in accordance with the invention. These two figures are included here tohelp establish a part of the underlying background of this invention.

FIG. 14 illustrates still another processing approach which utilizes asingle-crystalline material seed 44 which rests in a tiny indentationformed in an appropriate layer 45 of a supporting material, such assilicon dioxide. See 44 lies adjacent an amorphous layer 50 of silicon.Laser processing takes place with initial illumination of the seed,followed by the laser-beam progression from the seed in a definedpattern over the amorphous silicon material. This action causes thesingle crystalline character of the seed 44 to become telegraphed intothe internal structure of silicon layer 50, thus to characterize theinternal crystalline structure in this layer to make it more nearlysingle crystalline in structure at the conclusion of processing.

FIG. 15 illustrates, in simplified fragmentary form, a monolithic layerstructure 52 of processed, initially amorphous material which as beenprocessed in an array fashion, and at discrete locations, to create amonolithic array of mechanical devices such as the devices shown at 54.While it is certainly possible that each and every one of devices 54 isessentially the same in construction, and intended to perform the samekind of function, it is entirely possible, according to practice of theinvention, to differentiate the functionalities and thus the structuresof these arrayed elements.

It should thus be apparent that a unique process capable of creating awide range of unique mechanical devices, down to small molecular clusterdevices, with a high degree of precise control over internal mechanicalproperties, is made possible by the present invention. Also madepossible is the opportunity to do this insofar as laser processing isinvolved, in a completely atmospheric environment and at roomtemperature, and also in a manner which is one that does not attack anddestroy supporting structure, such as substrate structure.

Accordingly, while several embodiments and manners of practicing theinvention, and a system for doing all of this, have been illustrated anddescribed herein, it is appreciated that variations and modificationsmay be made without departing from the spirit of the invention.

1. A method of forming, from a precursor, semiconductor material havingselectively and controllably changeable crystalline-structure-relatedmechanical properties, a semiconductor mechanical device possessing (a)a predetermined configuration, and therein (b) a set of such mechanicalproperties, that are desired for the performance by the completed deviceof a pre-chosen mechanical task, said method comprising placing aprecursor body of such semiconductor material in a processing zone,selecting a volumetric region in that body which is suitable (a) for thecreation therefrom of the desired, predetermined device configuration,and (b) for the establishment therein of the desired set ofcrystalline-structure-related mechanical properties, within theprocessing zone, subjecting the selected region to a controlled changingof the crystalline structure therein, and thus of the related mechanicalproperties, and by that process, achieving, in the selected region, thedesired set of mechanical properties.
 2. The method of claim 1 whereinthe precursor material takes the form of one of an amorphous material,and nanocrystalline material, a microcrystalline material andpolycrystalline material.
 3. The method of claim 1 wherein the precursormaterial takes the form of one of silicon, germanium andsilicon-germanium.
 4. The method of claim 1 wherein said placing of aprecursor body of semiconductor material in the processing zone involvesplacing such material on the surface in a supporting substrate where thesubstrate is formed from one of glass, quartz, plastic materials, metalfoil materials, dielectric materials, and piezoelectric materials. 5.The method of claim 1 wherein the semiconductor mechanical deviceproduced is a MEMS device.
 6. The method of claim 1, wherein the body ofmaterial takes the form of a layer having a defined thickness, and saidsubjecting involves melting and re-crystallizing of zones in that layerthrough the full depth of the layer at the location of each zone.
 7. Themethod of claim 1, wherein the body of material takes the form of alayer having a defined thickness, and said subjecting involves meltingand re-crystallizing of zones in that layer through less than the fulldepth of the layer at the location of each zone.
 8. The method of claim1, wherein said subjecting is performed in a manner which differentiatesand distinguishes different zones in a region, whereby suchdifferentiated and distinguished zones possess, after the subjectingstep, different internal properties.
 9. The method of claim 1, whereinsaid subjecting is performed by a controlled energy beam which isdirected toward a surface of the material body.
 10. The method of claim9, wherein the controlled energy beam takes the form of a laser beam.11. The method of claim 10, wherein, during the subjecting step, thelocation of beam-body impingement moves over the mentioned surface ofthe body.
 12. The method of claim 1, wherein said subjecting isperformed by a pair of controlled energy beams which are directed towardopposite surfaces in the material body.
 13. The method of claim 12,wherein the controlled energy beams are laser beams.
 14. The method ofclaim 13, wherein, during the subjecting step, the locations ofbeam-body impingement move over such opposite surfaces in the body. 15.The method of claim 1, wherein the controlled changing of crystallinestructure produces an enlargement of internal grain size.
 16. A methodof making a task-specific, semiconductor mechanical device at leastpartially out of a chosen semiconductor material whose local mechanicalproperties are closely linked to internal crystalline structure, saidmethod comprising determining an appropriate spatial configuration forthe device, on the basis of said determining, deciding upon theappropriate distribution in such configuration of local mechanicalproperties needed for the finished device to be capable of performingthe intended specific task, and applying suitablecrystalline-structure-modifying processing to a body of the chosensemiconductor material to achieve therein a processed region whichpossesses both the determined appropriate spatial configuration for thedevice, and a distributed, local crystalline-structure arrangement thatproduces the decided-upon, distributed, local mechanical properties. 17.A semiconductor mechanical device-building method comprising selecting aparticular semiconductor mechanical device to build for the purpose ofperforming a particular task, in relation to said selecting, determiningfor the selected device a three dimensional-configuration, and an innermechanical properties characteristic within that configuration, suitedfor the particular task, choosing a semiconductor material for thecreation of the device, and selectively and controllably processing theinternal crystalline structure within the chosen semiconductor material,and within a region in that material matching the determined deviceconfiguration, thus to achieve within that region the desired,determined, inner mechanical properties for the selected particulartask.
 18. A semiconductor mechanical device for use in and with respectto a pre-chosen mechanical task comprising a body of semiconductormaterial having a three-dimensional, volumetric configuration suited forthe pre-chosen task, and within that semiconductor material body, acrystalline structure which is the result of controlled, prior-historyprocessing and changing of that structure, and which establishes theappropriate mechanical properties in the body for the performance of thepre-chosen task.
 19. An ambient-temperature method for creating, from aprecursor semiconductor material having selectively and controllablychangeable crystalline-structure-related mechanical properties, asemiconductor mechanical device possessing (a) a predeterminedconfiguration, and therein (b) a set of such mechanical properties, thatare desired for the performance by the completed device of a pre-chosenmechanical task, said method comprising placing a precursor body of suchsemiconductor material in a processing zone, selecting a volumetricregion in that body which is suitable (a) for the creation therefrom ofthe desired device configuration, and (b) for the establishment thereinof the desired set of crystalline-structure-related mechanicalproperties, within the processing zone, subjecting the selected regionto a controlled changing of the crystalline structure therein, and thusof the related mechanical properties, said subjecting taking place inthe context of a local-only material-body temperature rise, and by thatprocess, achieving, in the selected region, the desired set ofmechanical properties.
 20. A method of forming, from a semiconductorprecursor material having selectively and controllably changeablecrystalline-structure-related mechanical properties, a semiconductormechanical device possessing (a) a predetermined configuration, andtherein (b) a set of such mechanical properties, that are desired forthe performance by the completed device of a pre-chosen mechanical task,said method comprising, forming a semiconductor precursor body of suchsemiconductor material, placing that formed, semiconductor material bodyin a processing zone, within that zone, applying processing to that bodyto establish, within a selected region therein, an internal crystallinecondition which is characterized by possession of a set of the desiredcrystalline-structure-related mechanical properties, and at some pointin time during implementation of the method, creating from thesemiconductor material body the desired, predetermined deviceconfiguration, and doing this in a manner whereby, on completion of themethod, the desired configuration is substantially defined by materialprocessed in the selected region.
 21. A method of making a defined-task,micro-mechanical semiconductor device within a size range which, at thelower end therein, extends to single-crystal-level devices, said methodcomprising choosing for the creation of such a device a semiconductormaterial which possesses crystalline-structure-defining mechanicalproperties, selecting a target three-dimensional configuration and a setof mechanical properties effective to achieve such a device for thedefined task, and processing the crystalline structure of an appropriatethree-dimensional quantity of such chosen semiconductor material to meetthe selected target configuration and set of mechanical properties. 22.A system for forming, from a precursor semiconductor material havingselectively and controllably changeable crystalline-structure-relatedmechanical properties, a mechanical device possessing (a) apredetermined configuration, and therein (b) a set of such mechanicalproperties, that are desired for the performance by the completed deviceof a pre-chosen mechanical task said, system comprising, a processingzone adapted to receive a precursor body of such semiconductor material,a laser processing source, operable to direct a controlled beam of laserillumination onto such a precursor body placed within said processingzone, and computer structure operatively connected to all relevantcomponents in the system and operable to produce translated motion of apoint of impingement between a beam of laser radiation from said sourceover a surface of a precursor body of material within the processingzone in a manner which creates, within the precursor body, a changedcharacter of internal crystalline structure which produces desiredmechanical properties for an intended semiconductor mechanical devicethat is being built, with such crystalline changed structure residingafter processing, in a regional volume within the precursor materialcapable of defining the three dimensional configuration of the desiredmechanical device.